import { Universe, Cell } from "wasm-game-of-life";

const CELL_SIZE = 5; // px
const GRID_COLOR = "#CCCCCC";
const DEAD_COLOR = "#FFFFFF";
const ALIVE_COLOR = "#000000";

const universe = Universe.new();
const width = universe.width();
const height = universe.height();

const canvas = document.getElementById("game-of-life-canvas");
canvas.height = (CELL_SIZE + 1) * height + 1;
canvas.width = (CELL_SIZE + 1) * width + 1;

const ctx = canvas.getContext('2d');


const drawGrid = () => {
	ctx.beginPath();
	ctx.strokeStyle = GRID_COLOR;
  
	// Vertical lines.
	for (let i = 0; i <= width; i++) {
	  ctx.moveTo(i * (CELL_SIZE + 1) + 1, 0);
	  ctx.lineTo(i * (CELL_SIZE + 1) + 1, (CELL_SIZE + 1) * height + 1);
	}
  
	// Horizontal lines.
	for (let j = 0; j <= height; j++) {
	  ctx.moveTo(0,                           j * (CELL_SIZE + 1) + 1);
	  ctx.lineTo((CELL_SIZE + 1) * width + 1, j * (CELL_SIZE + 1) + 1);
	}
  
	ctx.stroke();
};

// Import the WebAssembly memory at the top of the file.
import { memory } from "wasm-game-of-life/wasm_game_of_life_bg";

const getIndex = (row, column) => {
  return row * width + column;
};

const drawCells = () => {
  const cellsPtr = universe.cells();
  const cells = new Uint8Array(memory.buffer, cellsPtr, width * height);

  ctx.beginPath();

  for (let row = 0; row < height; row++) {
    for (let col = 0; col < width; col++) {
      const idx = getIndex(row, col);

      ctx.fillStyle = cells[idx] === Cell.Dead
        ? DEAD_COLOR
        : ALIVE_COLOR;

      ctx.fillRect(
        col * (CELL_SIZE + 1) + 1,
        row * (CELL_SIZE + 1) + 1,
        CELL_SIZE,
        CELL_SIZE
      );
    }
  }

  ctx.stroke();
};

const renderLoop = () => {
	universe.tick();
  
	// drawGrid();
	drawCells();
  
	requestAnimationFrame(renderLoop);
};

drawGrid();
drawCells();
requestAnimationFrame(renderLoop);
